Statement - I : If the length of the conductor is doubled, the drift velocity will become half of the original value. (keeping potential difference unchanged).
Statement – II At constant potential difference, drift velocity is inversely proportional to the length of the conductor

We know that in a conductor, J=neV_d​ or ${\mathrm{V}}_{\mathrm{d}}=\frac{\mathrm{I}}{\mathrm{neA}}$

I = V/R​ and R = ρl​/A

So, the value of drift velocity becomes $V_d=\frac{V}{\left(ne\rho \right)l}.$.........(1)

From eq. 1 we can see V_d​ is inversely related to length l because voltage is given constant.

So, V_d​ $\propto$ 1/L

Therefore, if we double the length of the conductor then it's drift velocity becomes half.